Add device analytics middleware for data-driven responsive navigation decision

[Copilot]

Implements anonymous device type tracking to determine if mobile hamburger menu implementation justifies the effort based on actual traffic (30% mobile threshold per issue requirements).

Changes

Middleware & Analytics

• DeviceAnalyticsMiddleware: Thread-safe UserAgent classification (Mobile/Tablet/Desktop) with in-memory aggregation
• /DeviceAnalytics page: Real-time statistics dashboard with decision criteria display
• Device detection heuristics: iPad/tablet keywords → Tablet; Android without "mobile" → Tablet; iPhone/mobile → Mobile; default → Desktop

Integration

• Registered middleware in HTTP pipeline after UseRequestLocalization()
• Added Analytics navigation link in _Layout.cshtml

Testing

• Integration tests for UserAgent classification across device types
• Tests use CustomWebApplicationFactory to avoid database collision with parallel test execution

Privacy

• No PII collection - only aggregate device type counts
• Anonymous in-memory statistics only
• Privacy notice included in dashboard

Example Usage

// Middleware automatically tracks all requests
app.UseMiddleware<DeviceAnalyticsMiddleware>();

// Retrieve current statistics
var stats = DeviceAnalyticsMiddleware.GetStatistics();
Console.WriteLine($"Mobile: {stats.MobilePercentage:F2}%");

Screenshots

Analytics Dashboard

Dashboard displays device breakdown with decision threshold guidance. After ~1 week of data collection, if mobile traffic ≥ 30%, proceed with hamburger menu implementation.

Next Phase (Post-Data Collection)

If mobile ≥ 30%: Implement responsive hamburger menu for ≤375px screens with accessibility focus and pure CSS (no Tailwind dependency as noted in issue).

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• copilot.microsoft.com
  • Triggering command: /opt/microsoft/msedge/msedge --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --ignore-certificate-errors --use-angle=swiftshader-webgl --ignore-certificate-errors --crashpad-handler-pid=5141 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/.com.microsoft.Edge.scoped_dir.jyiVCR --change-stack-guard-on-fork=enable --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,11189740950603331162,9514024058580901471,262144 --enable-features=msMetricsLogFastStartup,msSendMetricsLogOnClose --disable-features=IgnoreDuplicateNavs,PaintHolding,Prewarm --variations-seed-version --trace-process-track-uuid=3190708989122997041 --enable-logging=stderr --log-level=0 (dns block)
  • Triggering command: /opt/microsoft/msedge/msedge --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --ignore-certificate-errors --use-angle=swiftshader-webgl --ignore-certificate-errors --crashpad-handler-pid=5140 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/.com.microsoft.Edge.scoped_dir.ZkPRhk --change-stack-guard-on-fork=enable --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,8377868810783681332,14933709638949223820,262144 --enable-features=msMetricsLogFastStartup,msSendMetricsLogOnClose --disable-features=IgnoreDuplicateNavs,PaintHolding,Prewarm --variations-seed-version --trace-process-track-uuid=3190708989122997041 --enable-logging=stderr --log-level=0 (dns block)
  • Triggering command: /opt/microsoft/msedge/msedge --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --ignore-certificate-errors --use-angle=swiftshader-webgl --ignore-certificate-errors --crashpad-handler-pid=5139 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/.com.microsoft.Edge.scoped_dir.MCB7w8 --change-stack-guard-on-fork=enable --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,18273167410963471777,9640053187149539141,262144 --enable-features=msMetricsLogFastStartup,msSendMetricsLogOnClose --disable-features=IgnoreDuplicateNavs,PaintHolding,Prewarm --variations-seed-version --trace-process-track-uuid=3190708989122997041 --enable-logging=stderr --log-level=0 (dns block)
• edge.microsoft.com
  • Triggering command: /opt/microsoft/msedge/msedge --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --ignore-certificate-errors --use-angle=swiftshader-webgl --ignore-certificate-errors --crashpad-handler-pid=5139 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/.com.microsoft.Edge.scoped_dir.MCB7w8 --change-stack-guard-on-fork=enable --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,18273167410963471777,9640053187149539141,262144 --enable-features=msMetricsLogFastStartup,msSendMetricsLogOnClose --disable-features=IgnoreDuplicateNavs,PaintHolding,Prewarm --variations-seed-version --trace-process-track-uuid=3190708989122997041 --enable-logging=stderr --log-level=0 (dns block)
  • Triggering command: /opt/microsoft/msedge/msedge --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --ignore-certificate-errors --use-angle=swiftshader-webgl --ignore-certificate-errors --crashpad-handler-pid=5141 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/.com.microsoft.Edge.scoped_dir.jyiVCR --change-stack-guard-on-fork=enable --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,11189740950603331162,9514024058580901471,262144 --enable-features=msMetricsLogFastStartup,msSendMetricsLogOnClose --disable-features=IgnoreDuplicateNavs,PaintHolding,Prewarm --variations-seed-version --trace-process-track-uuid=3190708989122997041 --enable-logging=stderr --log-level=0 (dns block)
  • Triggering command: /opt/microsoft/msedge/msedge --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --ignore-certificate-errors --use-angle=swiftshader-webgl --ignore-certificate-errors --crashpad-handler-pid=5140 --enable-crash-reporter=, --noerrdialogs --user-data-dir=/tmp/.com.microsoft.Edge.scoped_dir.ZkPRhk --change-stack-guard-on-fork=enable --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,8377868810783681332,14933709638949223820,262144 --enable-features=msMetricsLogFastStartup,msSendMetricsLogOnClose --disable-features=IgnoreDuplicateNavs,PaintHolding,Prewarm --variations-seed-version --trace-process-track-uuid=3190708989122997041 --enable-logging=stderr --log-level=0 (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>レスポンシブ対応検討: モバイルアクセス分析とハンバーガーメニュー</issue_title>
<issue_description>## 概要
モバイル・タブレット対応の検討とアクセス解析に基づく意思決定のためのデータ収集を実施します。

背景

会議で「条件付き高位優先度」として決定された課題で、実際のアクセスデータに基づいて実装判断を行う必要があります。

現状の課題

• 375px幅でナビゲーション水平リストが折り返しでタップ領域が小さい
• 768px幅タブレットでナビメニュー幅がギリギリ折り返し寸前
• モバイル閲覧割合の実データがない状態での判断リスク

実装予定内容（データ収集後判断）

1. ハンバーガーメニュー導入

   • 375px以下でのナビゲーション最適化
   • アクセシビリティ配慮を含む実装（推定2h弱）
   • Tailwind未導入のため生CSS対応

2. アクセスログ収集基盤

   • UserAgent解析による端末種別分類
   • 匿名集計ミドルウェア実装
   • プライバシー配慮設計

判断基準

• モバイル閲覧割合30%超: 早期価値あり → 実装
• 30%未満: 優先度を下げて他タスクを優先

前提タスク

1. ログ収集ミドルウェア実装（早期対応）
2. 1週間程度のデータ蓄積
3. アクセス解析とモバイル比率算出

リスク

• 判断データが出るまで実装保留のため、スケジュール影響の可能性
• 工数見積り（1.5h→2h弱）の不確実性

代替案

• CSS Grid/Flexboxによる現状改善（軽量対応）
• 段階的レスポンシブ改善

優先度

条件付き高位 - アクセスログデータ取得後に最終判断

関連ファイル

• Pages/Shared/_Layout.cshtml
• wwwroot/css/site.css
• Program.cs（ログ収集ミドルウェア）</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes レスポンシブ対応検討: モバイルアクセス分析とハンバーガーメニュー #544

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